Installing OS X 10.4 Onto Powermac G5 Issues

The other day I purchased a Powermac G5 2.0GHz duel core and 1gb of memory, but it didn't have a hard drive. I installed a 160gb hard drive into the Mac and have been attempting to install OS X on it with no success. This is what happens:

I downloaded a Mac OS X 10.4 install .toast file and burned it to a DVD using poweriso. I inserted the disk into the powermac and held down "C" to boot from CD. The powermac just shows the folder icon with a flashing question mark. After this, I tried booting while holding "Alt". After this loads, all I see is a grey screen with a refresh symbol on the right and a next arrow on the left. I cannot figure out how to get this to work! Please help. Thanks.